Sharing State Between Vanilla and React Apps with Redux

The problem statement

I want to share a common data state between vanilla js and react app.

What is in this POC

• We will create two similar counter apps in vanilla and react.
• The count should be stored in a common state
• If we update the count in vanilla, it should be reflected in react and vice-verse

Project Structure

Our project is divided into two main sections:

1. Root Directory: Contains core files for the vanilla JavaScript portion of the app.
2. react-mf Directory: Houses the React micro-frontend which interacts with the vanilla JavaScript part.

The architecture of the app can be checked at link here

Key Files and Their Roles

Root Directory

• index.html: This is the entry point of our app, setting up the HTML structure and including links to stylesheets and JavaScript files. It features two key div elements with id="app" and id="root", which are used to mount the vanilla JS app and the React micro-frontend, respectively.

• main.js: Acts as the main JavaScript file for initializing the vanilla JS part of the app. It handles the core logic and interacts with the shared state.

• counter.js: Contains the code responsible for dispatching actions to the Redux store. For instance, it dispatches an INCREMENT action to update the counter.

• store.js: Sets up the Redux store, which manages the application's state and ensures consistency between the vanilla JS and React parts of the app.

react-mf Directory

• App.jsx: The main React component of our micro-frontend. It utilizes the useState hook for local state management and subscribes to the Redux store to reflect the global state. It renders a button to dispatch an INCREMENT action and displays the current count from the store.

• main.jsx: The entry point for the React micro-frontend, where the React app is initialized and rendered.

How does it work

1. Create a basic vanilla js website using redux store.
2. Expose the created store to window element.

const store = createStore(reducer);
window.customStore = store

1. Make use of store.dispatch function in react to fire a store action.

<button onClick={() => store.dispatch({type: 'INCREMENT'})}>

1. Listen to changes in store using store.subscribe

store.subscribe(() => {
    setCount(store.getState().counter)
  })

You can find the full code in the GitHub repository.